delhi

'ello,
Just wondering since the C4 has an additional diff, does it mean it requires more quantities of diff oil? while the C2 doesn't require as much? please explain the differences b/t tranny and diffy oils for the C4 and C2.

Thanks!
D

gjvander

Two separate cases on the C4. Not connected in terms of fluids. Can't remember exact quantities, but something like 3.5 liters on the main transmission, and 1.5 liters on the front. Same fluid type for both front and rear. The lateral diff in the aft end runs in the same oil as the transmission gears.

Geo

C4TT

Anyone know how big a job it is to replace these fluids?

Bob Krantz

Really not too bad at all. Drop the plastic under trays (f and r). The drain and fill plugs are recessed socket type, so you need an appropriate allen wrench or socket. I think I remember 12 mm but don't quote me. Open the fill plug first, so if it is stuck, you find out before draining the lube. After draining and reinstalling the drain plug, you need to get the new lube into a hole on the side of the case. I use a small plastic hand pump I bought years ago that fits into a 1 qt Stalube bottle, though I used Mobil 1 synthetic gear lube for the 964. Fill to level of filler hole, install plug, mount the undertrays and off you go.
Bob K
1989 C4

Adrian

Dear D,
The C4 has two additional diffs and requires more fluid. C4 also uses more brake fluid and has a larger brake fluid reservoir.
Ciao,
Adrian
964C4